Organic electroluminescent illumination panel, manufacturing method thereof, and organic electroluminescent illumination device with spacers protruding from a second electrode

ABSTRACT

Provided is a long-life organic electroluminescent illumination panel which is flexible and, even when a load is applied by bending, impact or vibration, can suppress the occurrence of defects in an electrode layer and an organic layer containing an organic electroluminescent material, and which can suppress the occurrence of dark spots due to short circuiting. This organic electroluminescent illumination panel includes: a pair of electrode layers, at least one of which is transparent, between a flexible film substrate and a flexible film sealing material, at least one of which is transparent; and an organic layer containing an organic electroluminescent material which is sandwiched between the pair of electrode layers. This organic electroluminescent illumination panel has multiple spacers which are disposed on an electrode layer laminated on the flexible film substrate so as to pass through the organic layer and another electrode layer.

TECHNICAL FIELD

The present invention relates to an organic electroluminescentillumination panel, a method for manufacturing the same, and an organicelectroluminescent illumination device.

BACKGROUND

An organic EL illumination panel using light emission from organicelectroluminescence (organic EL) is formed by laminating a transparentelectrode layer, an organic EL layer and an electrode layer sequentiallyonto a transparent substrate and sealing them with a sealing material.Since a substrate used in such an organic EL illumination panel isrequired to have stiffness and transparency ensuring high transmissionto light emitting from organic EL, glass substrates have been used.However, such glass substrates are brittle, is not easy to handle, andis difficult to make a glass substrate having a thickness such as a thinfilm. As such an organic EL illumination panel requires miniaturization,slimming, light weight and flexibility, transparent and flexible resinfilm attracts attention as an alternative to glass substrate since theyare capable of winding as a roll, is easy to handle, is able tomanufacture organic EL efficiently, has an improved design properties,and is inexpensive.

As shown in FIG. 7, an organic EL illumination panel has a structurethat a transparent electrode layer (12), an organic layer (13) and anelectrode layer (14) are sequentially laminated onto a transparentsubstrate (11) followed by fixing a sealing material (15) to thetransparent substrate (11) via an adhesive (17) of a seal part (16), anda total thickness is about several mm. To obtain a flexible organic ELillumination panel, a transparent and flexible resin film is used forthe transparent substrate (11) and also a material having the sameflexibility as the substrate is used for the sealing material (15), sothat bending property and ductility are consistent between the substrateand the sealing material. However, when the organic EL illuminationpanel is bent, as shown in FIG. 8, the organic layer (13) having ahighly thin thickness of nm order or the electrode layer (14) may bedamaged due to contact and compression with the sealing material (15).

As an example of organic EL elements, it has been reported an organic ELelement that spacer layers are provided in regions having no electrodelayer on a substrate to fill gaps, and an organic material layer isprovided thereon, thereby suppressing the permeation of air into thegaps, the deterioration of the organic EL element due to moisturepresent in air, and the diminishment of luminous brightness due todamage caused by bending of the organic material layer (Patent document1), or an organic EL element panel that a sealing material having nospacer is used in regions with multi-level crossing of wirings so as tosuppress electrical contact between an upper wiring and a lower wiringeven if spacers are inserted under excess sealing pressure (Patentdocument 2).

Besides, it has been reported an organic EL element comprising a pixelelectrode, a counter electrode, an organic light-emitting layertherebetween, a mask spacer on a partition wall surrounding the pixelelectrode and an inorganic film on the partition wall so as to suppressto stick material of an auxiliary counter electrode to the mask spacerand peel when forming the auxiliary counter electrode by vapordeposition and an organic EL device using the organic EL element whichis able to suppress to occur defects of emission (Patent documents 3 and4).

In the field of such organic EL illumination panels, there is a need foran organic EL illumination panel which is sealed between a substrate anda sealing material made of a flexible substrate and be able to suppressthe occurrence of defects in an organic layer containing organic EL oran electrode layer even when bending force is applied to an organic ELillumination panel.

PRIOR ART DOCUMENTS Patent Documents

Patent document 1: JP-A 2005-166445

Patent document 2: JP-A 2009-110785

Patent document 3: JP-A 2007-73504

Patent document 4: JP-A 2011-154797

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

It is an object of the present invention to provide a long-life organicEL illumination panel which is flexible and, even when a load is appliedby bending, impact and vibration, can suppress the occurrence of defectsin an organic layer containing organic EL or an electrode layer, andwhich can suppress the occurrence of dark spots due to short circuiting;an organic EL illumination device using the same; and a method formanufacturing the same.

Means to Solve the Problems

The present invention relates to an organic EL illumination panelcomprising a pair of electrode layers, at least one of which istransparent, between a flexible film substrate and a flexible filmsealing material, at least one of which is transparent; and an organiclayer containing organic electroluminescence which is sandwiched betweensaid pair of electrode layers, wherein multiple spacers are disposed onan electrode layer laminated on the flexible film substrate so as topass through the organic layer and another electrode layer.

Further, the present invention relates to an organic EL illuminationpanel comprising a pair of electrode layers, at least one of which istransparent, between a flexible film substrate and a flexible filmsealing material, at least one of which is transparent; and an organiclayer containing organic electroluminescence which is sandwiched betweensaid pair of electrode layers, wherein multiple spacers are disposed onthe flexible film sealing material so as to be opposed to an electrodelayer laminated on the organic layer and above the organic layer.

Further, the present invention relates to an organic electroluminescentillumination device characterized by using the organicelectroluminescent illumination panel.

Further, the present invention relates to a method for manufacturing anorganic electroluminescent illumination panel comprising a pair ofelectrode layers, at least one of which is transparent, between aflexible film substrate and a flexible film sealing material, at leastone of which is transparent; and an organic layer containing organicelectroluminescence which is sandwiched between said pair of electrodelayers, wherein the method comprises laminating a photoresist film on anelectrode layer laminated on the flexible film substrate and patterningthe photoresist film by photolithography to form spacers so as to passthrough the organic layer and another electrode layer, or printing aspacer material on an electrode layer laminated on the flexible filmsubstrate by dispense coating, inkjet coating, or screen-flexo-gravureto form spacers so as to pass through the organic layer and anotherelectrode layer.

Further, the present invention relates to a method for manufacturing anorganic electroluminescent illumination panel comprising a pair ofelectrode layers, at least one of which is transparent, between aflexible film substrate and a flexible film sealing material, at leastone of which is transparent; and an organic layer containing organicelectroluminescence which is sandwiched between said pair of electrodelayers, wherein the method comprises laminating a photoresist film onthe flexible film sealing material and patterning the photoresist filmby photolithography to form spacers being opposed to an electrode layerlaminated on the organic layer and above the organic layer, or printinga spacer material on the flexible film sealing material by dispensecoating, inkjet coating, or screen-flexo-gravure to form spacers beingopposed to an electrode layer laminated on the organic layer and abovethe organic layer.

Effects of the Invention

An organic EL illumination panel of the present invention is flexibleand, even when a load is applied by bending, impact and vibration, cansuppress the occurrence of defects in an organic layer containingorganic EL or an electrode layer, and can suppress the occurrence ofdark spots due to short circuiting, and has long-life.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing an example of an organic ELillumination panel according to the present invention.

FIG. 2 is a view showing a cross-section along A-A′ line in FIG. 1 ofthe organic EL illumination panel according to the present invention.

FIG. 3 is a view showing a cross-section along B-B′ line in FIG. 1 ofthe organic EL illumination panel according to the present invention.

FIG. 4 is a cross-sectional view showing another example of an organicEL illumination panel according to the present invention.

FIG. 5 is a cross-sectional view showing another example of an organicEL illumination panel according to the present invention.

FIG. 6 is a view showing an operation mode for an example of an organicEL illumination panel according to the present invention.

FIG. 7 is a cross-sectional view showing a conventional organic ELillumination panel.

FIG. 8 is a view showing an operation mode for a conventional organic ELillumination panel.

DETAILED DESCRIPTION OF THE INVENTION

The organic electroluminescent illumination panel according to thepresent invention comprises a pair of electrode layers, at least one ofwhich is transparent, between a flexible film substrate and a flexiblefilm sealing material, at least one of which is transparent; and anorganic layer containing organic electroluminescence which is sandwichedbetween said pair of electrode layers, wherein the organicelectroluminescent illumination panel has multiple spacers which aredisposed on an electrode layers laminated on the flexible film substrateso as to pass through the organic layer and another electrode layer.

At least one of the flexible film substrate and the flexible filmsealing material (they are also referred to as flexible films) used inthe organic electroluminescent illumination panel should hastransparency, and the other may or may not be transparent. Specifically,a transparent flexible film substrate and a non-transparent flexiblefilm sealing material may be used.

The transparency of the flexible film substrate or the flexible filmsealing material should be able to transmit light emitting from theorganic EL contained in the organic layer such that the organic ELillumination panel can be operated, a high transmission rate beingpreferred. For example, a transmission rate to light emitting from theorganic EL is preferably 80% or more transmission based on a total lightamount, and more preferably 84% or more. The flexible film substrate andthe flexible film sealing material do not necessarily need to use thesame material, but it is preferred to use materials having similarbending stress. Specifically, preferred flexible films may includepolyesters such as polyethylene naphthalate (PEN), polyethyleneterephthalate (PET) or the like; acrylic resins such as polymethylmethacrylate, polyethyl methacrylate, polymethyl acrylate, polyethylacrylate or the like; polyethersulfone (PES), polycarbonate (PC); or thelike. For example, the flexible film substrate may have a thickness of20-300 μm, and the flexible film sealing material may have a thicknessof 50-200 μm.

These flexible films may have a gas barrier layer to suppress thepermeation of gases such as water. Preferably, such a gas barrier layermay be an inorganic layer comprising silicone nitride, silicone nitrideoxide, silicone oxide or the like, or may be a transparent layercomprising a hydrophobic resin layer such as olefin resins or ahydrophilic resin layer such as acrylic resins along with the inorganiclayer.

One of the pair of electrode layers is provided on the flexible filmsubstrate. If the flexible film substrate is transparent, then atransparent electrode layer is formed. The transparent electrode layertransmits light emitting from the organic EL contained in the organiclayer, so that the organic EL illumination panel is operated.Preferably, the transparent electrode layer has a high transmission rateto light emitting from the organic EL. For example, a transmission rateto light emitting from the organic EL is preferably 89% or moretransmission based on a total light amount. The transparent electrodelayer may supply either carriers of holes or electrons, but may beformed from a light-transmitting material such as indium tin oxide,indium zinc oxide or the like to make a positive electrode for supplyingholes. For example, the transparent electrode layer may have a thicknessof 100-300 nm.

The electrode layer mated with the transparent electrode layer is notlimited in light transmission. When the transparent electrode layer is apositive electrode formed from the foregoing light-transmittingelectrode materials, the electrode layer may be a light-shieldingnegative electrode for supplying electrons. Specifically, the electrodelayer may be a light-shielding negative electrode formed as a thin filmof a metal, for example aluminum, silver or the like. The electrodelayer may reflect light emitting from the organic layer toward thelight-transmitting electrode layer, and suppress a reduction in amountof light emitting from a light-emitting surface of the organic ELillumination panel. The electrode layer is preferably thick in terms ofvoltage drop due to wiring resistance, and may be 50-300 nm, forexample. Also, the electrode layer may be transparent by using alight-transmitting negative electrode material. If both of the flexiblefilm substrate and the flexible film sealing material are transparent, atransparent organic EL illumination panel may be formed. To connect theelectrode layer and a wiring member, one end of the electrode layer maybe preferably extended to form a connection part.

Multiple spacers are provided on the electrode layer on the flexiblefilm substrate. Preferably, the spacers may have a cylindrical shapesuch as a circular columnar or a hexagonal columnar, a spherical shape,or the like. When spacers having a linear shape or a large contact areaare provided, they are prone to impart stiffness to the organic ELillumination panel therefore it is difficult to maintain the panel'sflexibility. To the contrary, since columnar or spherical spacers havelow contact areas with flexible films, the organic EL illumination panelcan maintain its flexibility. With respect to a cross-sectional areaoccupied by one spacer in a cross-section parallel to a surfacedirection of the organic layer, the occupied cross-sectional area isdesirable to be large in terms of the function of spacers forsuppressing contact between the flexible film substrate and the flexiblefilm sealing material, while the occupied cross-sectional area isdesirable to be small in terms of avoiding perceiving spacers withoutorganic EL in the organic layer as portions without emitting lightvisually. Thus, it is preferred to select the cross-sectional areaconsidering the aforementioned issue. An cross-sectional area occupiedby one spacer in a cross-section parallel to a surface direction of theorganic layer preferably corresponds to an area of a circle having adiameter of 5 μm to 50 μm inclusive, and more preferably an area of acircle having a diameter of 8 μm to 20 μm inclusive. If the averagecross-sectional area corresponds to an area of a circle having adiameter of 5 μm or more, spacers may be more stably formed byphotolithography. If the average cross-sectional area corresponds to anarea of a circle having a diameter of 50 μm or less, spacers may not bevisually perceived and a high aperture ratio, i.e., a largelight-emitting area of the organic layer may be obtained.

To maintain contactless between the flexible film substrate and theflexible film sealing material and enlarge a light-emitting area of theorganic layer, the density of multiple spacers provided is preferablyfrom 100 spacers/cm² to 400 spacers/cm² inclusive in the organic layer,and more preferably from 100 spacers/cm² to 200 spacers/cm² inclusive.If the density of spacers is within said ranges, intervals betweenflexible films can be maintained and defects in the organic layer or theelectrode layers can be suppressed even when the organic EL illuminationpanel is bent.

The spacers have a height to pass through the organic layer and anotherelectrode layer with distal ends being protruded from the otherelectrode layer. Specifically, the distal ends preferably protrudeaverage 0.2 μm to 100 μm inclusive from a top surface of the otherelectrode layer, and more preferably average 1 μm to 30 μm inclusive.

The spacers may be made from resin materials or inorganic compounds aslong as it is a non-conductive material not to cause short-circuitingbetween the electrode layers. Specifically, the spacers may be made fromthe same materials as flexible films, or resists used inphotolithography of the electrode layers. In particular, materials arepreferred, which have strength to maintain intervals between flexiblefilms when the organic EL illumination panel is bent. Also, it ispreferred to select a spacer material considering density, productioneffectiveness and the like.

For example, the organic layer may have a structure that a holeinjection layer, a hole transporting layer, a light-emitting layercontaining organic EL, an electron transporting layer and an electroninjection layer are sequentially laminated. A plurality of carrierblocking layers may be provided to suppress the migration of holes orelectrons without emitting light from the light-emitting layer andenhance light-emitting effectiveness.

The hole injection layer is provided to reduce a height of an injectionbarrier to holes injected from the transparent electrode layer to theorganic layer, alleviate a difference in energy level between thepositive electrode and the hole transporting layer, and facilitate theinjection of holes injected from the positive electrode to the holetransporting layer. As materials for the hole injection layer from whichthe hole injection layer is formed, examples may include copperphthalocyanine or arylamine derivatives such as starburst-type aromaticamines, or these materials having doped an inorganic substance such asvanadium pentoxide or molybdenum trioxide or an organic substance suchas F4-TCNQ to reduce the injection barrier and lower driving voltage.

The hole transporting layer is provided to increase the migration rateof holes to the light-emitting layer. As materials for the holetransporting layer from which the hole transporting layer is formed,those having suitable ionization potential and electron affinity toprevent electrons from being leaked from the light-emitting layer arepreferred. Examples of materials for the hole transporting layer usedmay include triphenyldiamines such asbis(di(p-tolyeaminophenyl)-1,1-cyclohexane, TPD,N,N′-diphenyl-N—N-bis(1-naphthyl)-1,1′-biphenyl)-4,4′-diamine (α-NPD) orthe like, or starburst-type aromatic amines.

The light-emitting layer is used to recouple holes to electrons injectedfrom the electrodes and emit fluorescence and/or phosphorescence. Asmaterials from which the light-emitting layer is formed, examples mayinclude low molecular weight compounds such astris(8-quinolinol)aluminum complex (Alq3), bisdiphenylvinylbiphenyl(BDPVBi), 1,3-bis(p-t-butylphenyl-1,3,4-oxadiazolyl)phenyl (OXD-7),N,N′-bis(2,5-di-t-butylphenyl)perylene tetracarboxylic diimide (BPPC),1,4-bis(N-p-tolyl-N-4-(4-methylstyryl)phenylamino)naphthalene or thelike, or high molecular weight compounds such aspolyphenylenevinyl-based polymers or the like.

As other light-emitting materials, materials which comprise binarycomponents of a host and a dopant, and emit light from a dopant moleculeby transferring excitation energy generated by a host molecule to thedopant molecule may be used. As such binary light-emitting materials,the foregoing light-emitting materials, electron transporting materialsor hole transporting materials may be used. For example, those in whicha host quinolinol metal complex such as Alq3 is doped with4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyrano(DCM), aquinacridone derivative such as 2,3-quinacridone, or a coumarinderivative such as 3-(2′-benzothiazole)-7-diethylamino coumarin as adopant; a host electron transporting materialbis(2-methyl-8-hydroxyquinoline)-4-phenylphenol-aluminum complex isdoped with a condensed polycyclic aromatic compound such as perylene asa dopant; a host hole transporting material4,4′-bis(m-tolylphenylamino)biphenyl (TPD) is doped with rubrene as adopant; or a host carbazol compound such as 4,4′-biscarbazolylbiphenyl(CBP) or 4,4′-bis(9-carbazolyl)-2,2′-dimethylbiphenyl (CDBP) is dopedwith a platinum complex or an iridium complex such astris-(2-phenylpyridine)iridium complex (Ir(ppy)3),(bis(4,6-di-fluorophenyl)-pyridinate-N,C2′)picolinate iridium complex(FIr(pic)),(bis(2-(2′-benzo(4,5-α)thienyl)pyridinate-N,C2′)(acetylacetonate)iridiumcomplex (Btp2Ir(acac)), Ir(pic)3 or Bt2Ir(acac) as a dopant.

These light-emitting materials may be selected depending on alight-emitting color intended for an organic EL illumination device.Specifically, for green color, Alq3 and a dopant such as quinacridone,coumarin, Ir(ppy)3 or the like may used; for blue color, DPVBi and adopant such as perylene, distyrylarylene derivatives, FIr(pic) or thelike may be used; for green-bluegreen color, OXD-7 or the like may beused; for red-orange color, a dopant such as DCM, DCJTB, Ir(pic)3 or thelike may be used; for yellow color, a dopant such as rubrene,Bt2Ir(acac) or the like may be used. Also, to obtain white color light,a combination of host Alq3 and guest DCM (orange color) may be used aslight-emitting materials.

As the light-emitting layer for white color light, there may be athree-layer lamination structure in which each layer contains alight-emitting material emitting red, green and blue color,respectively; or a two-layer lamination structure in which each layercontains a light-emitting material emitting blue and yellow,respectively, as complementary colors; or a single-layer structurecomprising mixed light-emitting materials formed by co-depositing theselight-emitting materials for each color. Further, a light-emitting layermay be formed by arranging the light-emitting material corresponding toeach color layer in the three-layer or two-layer lamination structure asfine pixels of red, blue, green and the like in a plane.

As the carrier blocking layer, the hole blocking layer may be providedon the light-emitting layer. The hole blocking layer is provided toblock holes passing through the light-emitting layer without emittinglight and enhance recoupling holes to electrons in the light-emittinglayer. As materials from which the hole blocking layer is formed,2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), triphenyldiaminederivatives, triazole derivatives or the like may be used.

The electron transporting layer is provided to increase the migrationrate of electrons to the light-emitting layer. The electron transportinglayer is preferably formed from materials having suitable ionizationpotential and electron affinity to prevent holes from being leaked fromthe light-emitting layer. Examples of materials for the electrontransporting layer used may include organic substance, for exampleoxadiazole derivatives such as2-(4-biphenylyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole (Bu-PBD) or OXD-7,triazole derivatives, quinolinol-based metal complexes or the like, orthe foregoing organic materials having doped electron donor materialsincluding alkali metals such as lithium.

The electron injection layer is provided to facilitate the injection ofelectrons from the electrode layer to electron transporting layer as theinjection is difficult due to a large energy difference between the workfunction of a metal material such as aluminum used in forming thenegative electrode layer and the electron affinity (LUMO level) of theelectron transporting layer. As materials for the electron injectionlayer from which the electron injection layer is formed, materialshaving low work function, for example fluorides or oxides of alkalimetals such as lithium or cesium, or fluorides or oxides of alkali earthmetals such as calcium, or alloys such as magnesium silver or lithiumaluminum may be used.

For example, each of the organic layers provided between the electrodelayers may have a thickness of 1-500 nm, the total thickness being100-1000 nm.

Also, a sealing space formed by bonding the flexible film substrate ofthe organic EL illumination panel and the flexible film sealing materialvia a seal part may be preferably filled with a filler to inhibitcontact between the flexible film sealing material and the electrodelayers. As such filler, an inert gas or silicon containing a dewateringmaterial may be used. Among organopolysiloxanes, high viscosity-liquiddimethylpolysiloxane is preferred. The dewatering material may includecalcium oxide.

An example of the organic EL illumination panel is shown in FIG. 1 as aschematic view. FIG. 2 shows a cross-section along A-A′ line of FIG. 1,and FIG. 3 shows a cross-section along B-B′ line of FIG. 1. The organicEL illumination panel as shown in FIGS. 1-3 comprises a positiveelectrode (2) as the transparent electrode layer, an organic layer (3)and a negative electrode (4) as the electrode layer laminatedsequentially on a flexible film substrate (1), a flexible film sealingmaterial (5) being bonded to the flexible film substrate (1) via a sealpart (6) to form a sealing space (7). Multiple spacers (8) pass throughthe organic layer and the electrode layers and are disposed on thetransparent electrode layer such that distal ends of the spacers areplaced above a top surface of the negative electrode as the electrodelayer. In this figure, the distal ends of the spacers are not in contactwith a sealing material, but may be preferably in contact with a sealingmaterial in some cases.

An example of a method for manufacturing the organic EL illuminationpanel will be described.

The transparent electrode layer is formed on the transparent flexiblefilm substrate. The transparent electrode may be formed by depositing afilm of a material for the transparent electrode layer by sputtering,vapor deposition or CVD through a shadow mask, or patterning alight-transmitting electrode film uniformly formed from a material forthe transparent electrode layer by photolithography. To form aconnection part with a wiring member at one end of the transparentelectrode layer, the one end may be preferably extended.

Spacers are formed on the transparent electrode layer laminated on thetransparent flexible film substrate. Such spacers may be formed bydepositing a film of a spacer material by sputtering, vapor depositionor the like and patterning by photolithography, or by sputtering, vapordeposition or the like through a shadow mask. Also, such spacers may beformed by a printing method such as dispense coating, inkjet coating,screen/flexo/gravure or the like.

When the spacers are formed by photolithography, after the electrodelayer is formed, a photoresist film is formed on the electrode layer andthe photoresist film is patterned by photolithography to form thespacers. Photo resists may be negative types or positive types, but anegative type photoresist such as acrylic resins, novolacs, polyimidesor the like may be used, for example. By using photolithography, finepatterns in the order of 10 μm can be formed. Also, it is preferred thata transparent acrylic resin is used as the resist not to shield lightfrom the organic EL.

When the spacers are formed by printing, the procedure may be repeatedseveral time to obtain a desired height of the spacers. The spacersformed by printing have a size larger than by photolithography. Also, incase of printing, the height may be increased, a variety of materialsmay be selected, the manufacturing procedure may be simplified, simplyapparatuses may be used, the production effectiveness may be enhanced,and production costs may be reduced. Such spacers may be formed inregions not only with the organic layer but without the organic layerlaminated on the flexible film substrate.

Also, as shown in FIG. 4, when a photoresist film is patterned to formthe spacers (8), an insulation part (9) may be formed in the peripheryof the panel, serving as an electrode drawing part for the negativeelectrode. As a mask material used in pattering the photoresist film toform the spacers (8), a half tone mask or gray tone mask may be used, sothat the insulation part can have a height different from the spacers.The insulation part (9) allows manufacturing various light-emittingtypes of organic EL illumination panels. Also, a pattering process ofthe transparent electrode layer may be omitted as long as the underlyingtransparent electrode layer is uniformly formed.

Then, the organic layer is formed. The electron injection layer, theelectron transporting layer, the light-emitting layer, the holetransporting layer, the hole injection layer, and the hole blockinglayer may be formed using the foregoing materials as a desired shape bya vapor deposition method with resistance heating, a MBE method or alaser ablation method through a shadow mask. Also, if a polymer materialis used in forming these layers, each layer may be formed as a desiredshape by an inkjet method using a solution of the polymer material, oralternatively each layer may be formed as a desired shape by spincoating or slit coating a photosensitive coating solution followed byphotolithography.

The other electrode layer mated with the transparent electrode layer maybe formed by a method such as vapor deposition or sputtering on theorganic layer. To form a connection part with a wire member at one endof the electrode layer, the one end may be preferably extended.

Then, the flexible film sealing material is bonded or welded to theflexible film substrate on which the organic layer and the electrodelayers are formed through a seal part, and the organic layer and theelectrode layers are sealed within a sealing space. As the seal part, anUV-curable or heat-curable adhesive including epoxy resins or acrylicresins may be used. A bonded surface of the flexible film substrate andthe flexible sealing material is subjected to a surface treatment suchas local plasma treatment under normal pressure or coupling treatment toincrease the adhesion of the seal part. Alternatively, a laminate methodmay be applied. At this time, the procedure is performed under an inertgas such as nitrogen and also an inert gas is filled in the sealingspace, thereby obtaining the organic EL illumination panel.

Also, after the organic layer and the electrode layer are sealed,silicon containing a collector such as calcium oxide may be filled in asealing space. As a result, constant inner pressure is maintained, andcontact between the electrode layer or the organic layer and the sealingmaterial is suppressed by a synergic effect with spacers, so thatdefects in the electrode layers or the organic layer can be suppressedeven when the organic EL illumination panel is bent.

Also, the organic EL illumination panel according to the presentinvention may have spacers provided to be opposed to the electrode layerwhich is laminated on the organic layer on the flexible film sealingmaterial and above the organic layer. As shown in the cross-sectionalview of FIG. 5, spacers are provided on the flexible film sealingmaterial (5 b). In this figure, the same reference numbers as in FIG. 1denotes the same members as the members of the organic EL illuminationpanel shown in FIG. 1, respectively. The spacers (8 b) provided on theflexible film sealing material (5 b) may have the same shape, material,density and area occupied in the organic layer as the spacers (8) of theorganic EL illumination device shown in FIG. 1. Holes (8 c) forinserting the spacers (8 b) are provided in regions opposed to thespacers (8 b) on the electrode layer (4) and the organic layer (3), thespacers being inserted until reaching the transparent electrode (2).

The spacers (8 b) formed on the flexible film sealing material may havea height to allow their distal ends to contact with the transparentelectrode layer (2), but it is preferred to have a height to maintaincontactless in view of an interval variation of the substrate whenbending. Specifically, the height is preferably from 50 μm to 500 μm,depending on a height of the sealing space.

Such spacers (8 b) may be formed on the flexible film sealing materialusing the same method as the spacers (8). To form the holes (8 c) forinserting the spacers (8 b) provided in the electrode layer (4) and theorganic layer (3), the organic layer and the electrode layer may beformed using a shadow mask not to form a layer at the holes.

As shown in FIG. 6, the organic EL illumination panel can maintain aninterval between the electrode layer (4) and the flexible film sealingmaterial (5) by the spacers (8, 8 b), and can suppress contact betweenthe electrode layer and the flexible film sealing material. As a result,defects in the electrode layer or the organic layer can be suppressed.

Also, for an organic EL illumination device in which the organic ELelement is applied, a lighting circuit, a control circuit for thelighting circuit and the like are provided, these circuits beingconnected via wiring connected to a connection part formed by extendingone end of each of the transparent electrode layer and the matedelectrode layer of the organic EL element. An external power supply maybe provided for the transparent electrode layer and the electrode layertherethrough. The wiring having a width over the entire width of one endof the electrodes may be used to suppress an increase in resistance ofthe connection part. As the wiring, a flexible film such as copperpolyimide may bee used. Such an organic EL illumination devices may beapplied to a backlight for a liquid crystal display or the like.

EXAMPLES

Hereinafter, the lithium ion secondary batter according to the presentinvention will be described in detail.

Example 1

A transparent conductive film of indium tin oxide (ITO) was formed andpatterned on a polyethylene naphthalate-based film having 200 μmthickness by sputtering through a shadow mask to form a transparentelectrode layer. A negative type light sensitive acrylic resin solutionas a photoresist was coated on the transparent electrode layer followedby heating. Then, spacers having diameter 15 μm and height 5 μm wereformed on the transparent electrode layer at the density of 100spacers/cm². Then, using Cu-Pc (copper phthalocyanine) as a holeinjection material,α-NPD(N,N′-diphenyl-N—N-bis(1-naphthyl)-1,1′-biphenyl)-4,4′-diamine) asa hole transporting material, CBP (4,4′-biscarbazolylbiphenyl) havingdoped Ir(ppy)₃ (tris-(2-phenylpyridine)iridium complex), Btp₂Ir(acac)(bis(2-(2′-benzo(4,5-α)thienyl)pyridinate-N,C2′)(acetylacetonate)iridium complex) and furtherCBP having doped FIr(pic)(bis(4,6-di-fluorophenyl)-pyridinate-N,C2′)picolinate iridium complex)as a light-emitting material, BCP(2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) as a hole blockinglayer, Alq3 as an electron transporting layer, and LiF as an electroninjection material, these materials were sequentially deposited by vapor(heating) deposition through a mask to form an organic layer. A negativeelectrode was formed by vapor (heating) deposition of aluminum on theorganic layer. A thickness of the resulting organic EL element partwhich comprised the electrode layers and the organic layer sandwichedthere between was 285 nm as the sum of the organic layer and thenegative electrode layer. The spacers were protruded 4.7 μm from a topsurface of the negative electrode. Then, a film having 100 μm thicknessmade of the same material as the flexible film substrate was bonded tothe flexible film substrate on which the organic EL element part usingan epoxy adhesive under nitrogen atmosphere to make an organic ELillumination panel. At this time, plasma surface treatment under normalpressure was performed on a bonded area of the surface of the flexiblefilm substrate was performed to increase adhesion.

When lighting was performed at the constant current of 25 A/m² as adriving current, driving voltage was 4.6V and brightness was 980 cd/m².

[Vibration Test]

The organic EL illumination panel was fixed to a fixing jig and a loadof vibration frequency 5-100 Hz and acceleration 30 G was applied ineach of x, y and z directions for 1 minute. This action was repeated 10times. Then, the lighting of the panel was performed. All panels oftested 10 panels were lighted.

[Impact Test]

The organic EL illumination panel was fixed to a fixing jig and a loadof acceleration 30 G was applied in each of x, y and z directions for 10msec. This action was repeated 3 times. Then, the lighting of the panelwas performed. All panels of tested 10 panels were lighted.

[Bending Test]

Each of left and right sides against a center of the organic ELillumination panel was bent by 60 degrees and this action was repeated30 times. Then, the lighting of the panel was performed. All panels oftested 10 panels were lighted.

Comparative Example

An organic EL illumination panel was manufactured using the same methodas in Example 1 except for providing no spacer, and tests were performedon the resulting product. In the vibration test, 8 panels of tested 10panels were not lighted. In the impact test, none panels of tested 10panels were not lighted. In the bending test, 9 panels of tested 10panels were not lighted.

From these results, it was demonstrated that the organic EL illuminationpanel with no spacer exhibited short or leak, while the organic ELillumination panel of the present invention suppressed the occurrence ofdefects in the organic layer or the electrode layer under bending,vibration or impact.

The present application incorporates herein by reference PatentApplication No. 2012-079905 filed on Mar. 30, 2012 in its entirety.

THE DESCRIPTION OF REFERENCE NUMBERS

1 flexible film substrate

2 transparent electrode layer

3 organic layer

4 electrode layer

5, 5 b flexible film sealing material

8, 8 b spacer

INDUSTRIAL APPLICABILITY

The present invention is applicable to all of industrial fieldsrequiring a surface light source, and more particularly to a surfacelight source for various illumination devices, as well as a surfacelight source for various display devices, and display devices ofpersonal computers or terminals such as cellular phones ormultifunctional cellular phones.

The invention claimed is:
 1. A method for manufacturing an organicelectroluminescent illumination panel comprising a pair of first andsecond electrode layers, at least one of which is transparent, the pairof the first and second electrode layers being positioned between aflexible film substrate and a flexible film sealing material, at leastone of the flexible film substrate and the flexible film sealingmaterial being on a same side as a transparent electrode layer of thefirst and second electrode layers, at least one of the flexible filmsubstrate and the flexible film sealing material being transparent, theorganic electroluminescent illumination panel further comprising anorganic layer containing an organic electroluminescence, the organiclayer being sandwiched between the first and second electrode layers,the method comprising: laminating the first electrode layer on theflexible film substrate, the first electrode layer extending to frontand back end surfaces of the flexible film substrate to form a firstconnection part with a wiring member; forming a photoresist film on thefirst electrode layer; patterning the photoresist film byphotolithography to form spacers having a cylindrical shape so as tohave a height to pass through the organic layer and the second electrodelayer with distal ends thereof being protruded from the second electrodelayer; laminating the organic layer and the second electrode layer inthis order on the first electrode layer so that the second electrodelayer is formed on the flexible film substrate, wherein the secondelectrode layer is extended to the both end surfaces of the flexiblefilm substrate to form a second connection part with a wiring member;and providing the flexible film sealing material via a seal part formedat front and back end portions of the first electrode layer and at twoside end portions of the second electrode layer which are formed on theflexible film substrate so that the flexible film sealing material isnot in contact with the distal ends of the spacers, and that the sealpart exists inside of the first and second connection parts.
 2. A methodfor manufacturing an organic electroluminescent illumination panelcomprising a pair of first and second electrode layers, at least one ofwhich is transparent, the pair of the first and second electrode layersbeing positioned between a flexible film substrate and a flexible filmsealing material, at least one of the flexible film substrate and theflexible film sealing material being on a same side as a transparentelectrode layer of the first and second electrode layers, at least oneof the flexible film substrate and the flexible film sealing materialbeing transparent, the organic electroluminescent illumination panelfurther comprising an organic layer containing an organicelectroluminescence, the organic layer being sandwiched between thefirst and second electrode layers, the method comprising: laminating thefirst electrode layer on the flexible film substrate, the firstelectrode layer extending to front and back surfaces of the flexiblefilm substrate to form a first connection part with a wiring member;applying a spacer material on the first electrode layer by dispensecoating, inkjet coating, or screen-, flexo-, or gravure-printing to formspacers having a cylindrical shape so as to have a height to passthrough the organic layer and the second electrode layer with distalends thereof being protruded from the second electrode layer; laminatingthe organic layer and the second electrode layer in this order on thefirst electrode layer so that the second electrode layer is formed onthe flexible film substrate, wherein the second electrode layer isextended to the both end surfaces of the flexible film substrate to forma second connection part with a wiring member; and providing theflexible film sealing material via a seal part formed at front and backend portions of the first electrode layer and at two side end portionsof the second electrode layer which are formed on the flexible filmsubstrate so that the flexible film sealing material is not in contactwith the distal ends of the spacers, and that the seal part existsinside of the first and second connection parts.
 3. An organicelectroluminescent illumination panel comprising: a pair of first andsecond electrode layers, at least one of which is transparent, the pairof the first and second electrode layers being positioned between aflexible film substrate and a flexible film sealing material, at leastone of the flexible film substrate and the flexible film sealingmaterial being on a same side as a transparent electrode layer of thefirst and second electrode layers, at least one of the flexible filmsubstrate and the flexible film sealing material being transparent, theorganic electroluminescent illumination panel further comprising anorganic layer containing an organic electroluminescence, the organiclayer being sandwiched between the first and second electrode layers,wherein the first electrode layer is disposed on the flexible filmsubstrate, and is extended to front and back surfaces of the flexiblefilm substrate, and is a first connection part with a wiring member;wherein the organic electroluminescent illumination panel furthercomprises multiple spacers having a cylindrical shape fixed on the firstelectrode layer so as to pass through the organic layer and the secondelectrode layer, each of the multiple spacers having an unattached endthat is free to move, and a seal part formed on front and back endportions of the first electrode layer and two side portions of thesecond electrode layer which are formed on the flexible film substrateso that the flexible film sealing material is not in contact withrespective distal ends of the multiple spacers, and that the seal partexists inside of the first and the second connection parts; wherein theorganic layer and the second electrode layer are laminated in this orderon the first electrode layer so that the second electrode layer isformed on the flexible film substrate extended to two side end surfacesof the flexible film substrate, and the two side end surfaces being asecond connection part with a wiring member.
 4. An organicelectroluminescent illumination device using the organicelectroluminescent illumination panel according to claim
 3. 5. Themethod for manufacturing the organic electroluminescent illuminationpanel according to claim 1, wherein the first electrode layer and theflexible film substrate are transparent, and the thickness of theflexible film substrate is 20 to 300 μm, the thickness of the flexiblefilm sealing material is 50 to 200 μm, and a transmission rate of atleast one of the flexible film substrate and the flexible film sealingmaterial of light emitting from the organic electroluminescence is 80%or more transmission based on a total light amount.
 6. The method formanufacturing the organic electroluminescent illumination panelaccording to claim 1, wherein the flexible film substrate and theflexible film sealing material comprise a resin film, and the resin filmcomprises at least one selected from the group consisting ofpolyethylene naphthalate (PEN), polyethylene terephthalate (PET),polymethyl methacrylate, polyethyl methacrylate, polymethyl acrylate,polyethyl acrylate, polyethylsulfone (PES), and polycarbonate (PC). 7.The method for manufacturing the organic electroluminescent illuminationpanel according to claim 1, wherein at least one of the flexible filmsubstrate and the flexible film sealing material comprises a resin filmand a gas barrier layer configured to suppress permeation of gases. 8.The method for manufacturing the organic electroluminescent illuminationpanel according to claim 1, wherein the organic layer has a thickness of100 nm to 1000 nm.
 9. The method for manufacturing the organicelectroluminescent illumination panel according to claim 2, wherein thefirst electrode layer and the flexible film substrate are transparentand the thickness of the flexible film substrate is 20 to 300 μm, thethickness of the flexible film sealing material is 50 to 200 μm, and atransmission rate of at least one of the flexible film substrate and theflexible film sealing material of light emitting from the organicelectroluminescence is 80% or more transmission based on a total lightamount.
 10. The method for manufacturing the organic electroluminescentillumination panel according to claim 2, wherein the flexible filmsubstrate and the flexible film sealing material comprise a resin film,and the resin film comprises at least one selected from the groupconsisting of polyethylene naphthalate (PEN), polyethylene terephthalate(PET), polymethyl methacrylate, polyethyl methacrylate, polymethylacrylate, polyethyl acrylate, polyethylsulfone (PES), and polycarbonate(PC).
 11. The method for manufacturing the organic electroluminescentillumination panel according to claim 2, wherein at least one of theflexible film substrate and the flexible film sealing material comprisesa resin film and a gas barrier layer configured to suppress permeationof gases.
 12. The method for manufacturing the organicelectroluminescent illumination panel according to claim 2, wherein theorganic layer has a thickness of 100 nm to 1000 nm.
 13. The organicelectroluminescent illumination panel according to claim 3, wherein thethickness of the flexible film substrate is 20 to 300 μm, the thicknessof the flexible film sealing material is 50 to 200 μm, and atransmission rate of at least one of the flexible film substrate and theflexible film sealing material of light emitting from the organicelectroluminescence is 80% or more transmission based on a total lightamount.
 14. The organic electroluminescent illumination panel accordingto claim 3, wherein an average cross-sectional area occupied by onespacer, of the multiple spacers, in a cross-section parallel to asurface direction of the organic layer corresponds to an area of acircle having a diameter of 5 μm to 50 μm inclusive.
 15. The organicelectroluminescent illumination panel according to claim 3, wherein themultiple spacers in a cross-section parallel to a surface direction ofthe organic layer are present in a density from 100 spacers/cm² to 400spacers/cm² inclusive.
 16. The organic electroluminescent illuminationpanel according to claim 3, wherein an inert gas or silicone containinga dewatering material is filled in a gap between the flexible filmsubstrate and the flexible film sealing material.
 17. The organicelectroluminescent illumination panel according to claim 3, wherein theflexible film substrate and the flexible film sealing material comprisea resin film, and the resin film comprises at least one selected fromthe group consisting of polyethylene naphthalate (PEN), polyethyleneterephthalate (PET), polymethyl methacrylate, polyethyl methacrylate,polymethyl acrylate, polyethyl acrylate, polyethylsulfone (PES), andpolycarbonate (PC).
 18. The organic electroluminescent illuminationpanel according to claim 3, wherein at least one of the flexible filmsubstrate and the flexible film sealing material comprises a resin filmand a gas barrier layer configured to suppress permeation of gases. 19.The organic electroluminescent illumination panel according to claim 3,wherein the organic layer has a thickness of 100 nm to 1000 nm.